No! Unless you have extra time.

I don't recommend Sikkim for foreigners because the awesome sites are simply offlimits.

Gangtok - Nice place. Lovely small city (MG road is awesome pedestrian district)

Tsangu - Lovely but by itself is not worth it (wouldn't start freezing even a bit by that time IIRC).

Pelling - Not been there, but pretty much known for views of Kanchenjunga

Gurudongmar - Amazing lake at 5000+m altitude

Yume Samdong - Come November and the flowers would be in bloom. Sight for sore eyes

Zero point/Lachung - End of the road, close to China - decent vistas

and several other treks etc in that region.

Kanchendjunga views are good BUT kindly realize that you are only getting half the package!

NOOOO! It is overrun by diesel fumes, mad traffic, antiquated shabby buildings and just plain mad rush (try going there around/post pooja time - mayhem!) - full of completely overrated tourist points - the real joy is views of Kanchenjunga. The endless traffic jams don't help the cause either!

Yeah!! It is a nice quiet place with lovely people, decent small bit of sightseeing and (yeah!) Kanchenjunga views!